The Bible is God’s word to Man. And it is a progressive book. God did not reveal His secrets all at once but over many hundreds of Years.
The secret things belong unto the LORD our God: but those things which are revealed belong unto us and to our children for ever, that we may do all the words of this law. (Deuteronomy 29:29)
It is the glory of God to conceal a thing: but the honour of kings is to search out a matter. (Proverbs 25:2)
I would seek unto God,” Job said, “and unto God would I commit my cause: Which doeth great things and unsearchable; marvellous things without number (Job 5:8-9).
Great is the LORD, and greatly to be praised; and his greatness is unsearchable (Psalm 145:3).
Great is our Lord, and of great power: his understanding is infinite (Psalm 147:5).
…There is no searching of his understanding (Isaiah 40:28).
And they understood none of these things: and this saying was hid from them, neither knew they the things which were spoken. (Luke 18:34)
For as yet they knew not the scripture, that he must rise again from the dead. (John 20:9)
But as it is written, Eye hath not seen, nor ear heard, neither have entered into the heart of man, the things which God hath prepared for them that love him. (1 Corinthians 2:9).
O the depth of the riches both of the wisdom and knowledge of God! how unsearchable are his judgments, and his ways past finding out! (Romans 11:33)
…that I should preach among the Gentiles the unsearchable riches of Christ; (Ephesians 3:8).
In this age of Grace, God has revealed many secrets but again, not all of them. Daniel and John (Revelation) have recorded that there are some secrets yet to come.
Daniel 12:8-9 And I heard, but I understood not: then said I, O my Lord, what shall be the end of these things? And he said, Go thy way, Daniel: for the words are closed up and sealed till the time of the end.
Revelation 10:4 And when the seven thunders had uttered their voices, I was about to write: and I heard a voice from heaven saying unto me, Seal up those things which the seven thunders uttered, and write them not.